title: Language-specific cortical activation patterns for verbal fluency tasks in Japanese as assessed by multichannel functional near-infrared spectroscopy.
abstract: In Japan, verbal fluency tasks are commonly utilized as a standard paradigm for neuropsychological testing of cognitive and linguistic abilities. The Japanese "letter fluency task" is a mora/letter fluency task based on the phonological and orthographical characteristics of the Japanese language. Whether there are similar activation patterns across languages or a Japanese-specific mora/letter fluency pattern is not certain. We investigated the neural correlates of overt mora/letter and category fluency tasks in healthy Japanese. The category fluency task activated the bilateral fronto-temporal language-related regions with left-superior lateralization, while the mora/letter fluency task led to wider activation including the inferior parietal regions (left and right supramarginal gyrus). Specific bilateral supramarginal activation during the mora/letter fluency task in Japanese was distinct from that of similar letter fluency tasks in syllable-alphabet-based languages: this might be due to the requirement of additional phonological processing and working memory, or due to increased cognitive load in general.
authors.affiliation: Applied Cognitive Neuroscience Laboratory, Research and Development Initiatives, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan.
authors.forename: Haruka
authors.initials: H
authors.lastname: Dan
authors.forename: Ippeita
authors.initials: I
authors.lastname: Dan
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Sano
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kyutoku
authors.forename: Keiji
authors.initials: K
authors.lastname: Oguro
authors.forename: Hidenori
authors.initials: H
authors.lastname: Yokota
authors.forename: Daisuke
authors.initials: D
authors.lastname: Tsuzuki
authors.forename: Eiju
authors.initials: E
authors.lastname: Watanabe
mesh_terms: D000328:Adult; D044466:Asian People; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D005260:Female; D006801:Humans; D007802:Language; D008297:Male; D008875:Middle Aged; D012815:Signal Processing, Computer-Assisted; D019265:Spectroscopy, Near-Infrared; D013060:Speech / Q000502:physiology*; D055815:Young Adult
keywords: Aphasia; Attention; Culture-specificity; Mora; Optical topography; Phonological word fluency; Semantic word fluency; Syllable; Task difficulty; fNIRS